Endless flexible belt



June 20, 1939. ss Bg 2,163,347

ENDLESS FLEXIBLE BELT Filed Feb. 17, 1936 EA/Qssp'zh 6 6716,

Patented June 20, 1939' I UNITED STATES PATENT oFFlet;

ENDLESS FLEXIBLE BELT Ernest Nassimbcne, Denver, 0010., assignorto TheGates Rubber Company, Denver, 0010., a corporation of ColoradoApplication February 17, 1936, Serial No. 64,410 Claims. (Cl. 74-233)This invention relates to improvementsinflexof the belt may be formed bythe uncovered ible belts, preferably of the V-type, which has rubber. lsloping side walls adapted to contact with the With these and otherobjects in view, the inadjacent sides of one or more grooved pulleys,vention consists in certain details of construction 5 the inner surfaceof the belt not touching the and combinations and arrangements of parts,all 5 bottom of the groove, whereby the belt wedges as will hereinafterbe more fully described and in the groove and thus insures tight contactwith the novel features thereof particularly pointed the pulley. out inthe appended claims.

The invention is especially applicable. to the In the accompanyingdrawing production of endless or spliced flexible V-belts, Figure 1 is aside elevation of a V-belt; 10 for use on adjustable pulleys, forinstance of the Fig. 2 is a sectional view taken transversely of typewherein the sides of the pulley may be adthe belt on the line 22 of Fig.1; justed toward and away from each other, where- Fig. 3 is afragmentary sectional view taken by the width of the groove is varied toposition longitudinally of the belt on the line 8-3 of the beltrelatively to the center of rotation of Fig. 2; and 15 the pulley,thereby varying the speed of the belt Fig. 4 is a similar view'illustrating a modified and pulley. Generally stated, the primary obformof belt.

ject of the invention is to provide a flexible belt of course, the majorportion, or what might wherein the disintegration of the belt or the betermed the body portion, of the belt, may be separation of the elementscomposing the same composed of various structural elements. In the go isgreatly reduced and the life of the .belt cor- Present instance. t isshown s being mposed respondingly increased. Specifically, the invenf aninner layer D of be protected y tion contemplates the incorporation inthe belt covering which extends across the bottom of means which willsubstantially eliminate transinner face of the belt as well as the sidesI! 2 verse flexing of the belt while at the same time of the belt. Nextto, or above, the rubber III. as allowing the belt to freely flex aroundthe sheave there is a y r of bbe zed woven fabric 13. and straighten outbetween the sheaves, thus re- Fabric B y be p if ne s y. t0 build pduoing to a minimum the amount of relative this layer o a thickness Suchs ay be demovement or shifting of the several elements consired in the Pl r type of belt under construcstituting the belt. The presentconstruction also tiOh- When the fabric I3 is used, it y be cut 80 aidsin maintaining the shape of the belt in cross either on the ia or str it- Next ab v s section, regardless of the diameter of the pulleys,speak, this rubberized ve fabric, is a Subt fi t a, r uniform wear andlonger stantially inextensible core composed of cords life for the belt.l4 embedded in rubber compound. This core is Preferably, these reinforcemeans consist 01' formed by the cords P p y cushioned and 35 a pluralityof transversely disposed elements extending longitudinally of the beltor substanwhich may be formed of comparatively hard rub- P y along heneutral, axis of the belt, all as her and which are substantially rigidtransverse- 15 common Prachse n the A the P ly of the belt, but are soembodied in the mm; t e construction described is believed preferable,

that the several ribs, asa group, are free to flex but as sthtedl it ybfivalied as desired- 4o longitudinally of the belt. These reinforceeletween lthis yportion, the outer surface of ments are located betweenthe neutral axis of which may Sald to P formed by the the belt and theouter surface of the belt as it and the term surface t belt passesaround the pulley Preferably the the belt is provided with means whichwill resist cesses formed between the transverse reinforce transverseflexing and cross'sectmnal deforma' tion thereof without interferingwith the longiribs are filled with comparatively soft rubber, and ifdesired, one or more layers of woven fabric tudmal flexing of the beltas it comes into material may be interposed between this filler iigf g gfg fl f around and leaves the De 5 and the ribs. In View of the use Ofthis Woven In a broad sense these reinforce means may be fabric at thispoint, it is possible that only aid to be composed of a plurality ofmembers exthe two side surfaces and the inner surface of tendingtransversely of th b lt b t th the be t need be Provided i a fabriccovering. core or neutral axis of the belt and the exterior rubberizedwoven fabric usually being used for surface of the belt, said meansbeing substan- I this purpose. In other words, the outer face tiallyrigid transversely of the belt but capable 55 of flexing, as a group,longitudinally of the belt. In the preferred construction, thesereinforce means are formed by a layer of comparatively hard rubber itnext to the core It, said layer of rubber being formed with transverselyextending ridges forming what may be described as lines of weaknessbetween the ridges, with the thickness of the ridges such as to resisttransverse flexing of the body of rubber it while the thickness of thereduced portions is such as to permit free flexing of the beltlongitudinally as it passes around pulleys. These reduced portions ofthe body of rubber I6 function as hinges between each two ribs or ridgesso that the entire mass of rubber it may be said to consist of aplurality of articulated, transversely extending ribs capable offlexing, as a group, longitudinally of the belt, but individuallycapable of resisting transver flexing of the belt.

'In order to give the exterior surface of the belt a finishedappearance, and to provide side walls having a maximum area of contact,the transverse depressions, formed by the so-called lines of weakness inthe rubber it, are fllled with a resilient flller I1, preferably acomparatively soft rubber compound. It is also preferred that a layer orsheet of fabric be interposed between this soft rubber filler and thehard rubber II, such fabric being indicated at I8.

It will be understood that after the several structural elements, thusdescribed, have been assembled, the assembled belt is subjected to theusual vulcanizing treatment.

In the finished belt illustrated, it will be observed that the coverextends only around the inner or bottom face of the belt and the twoside surfaces thereof, leaving the outer surface exposed. However, aspreviously indicated, the covering fabric may extend entirely around thebelt. When in use, the sloping side walls of the belt contact with theadjacent sides of the grooved pulley with the inner face of the beltspaced from the bottom of the groove so that the belt wedges in thegroove and thus insures maximum driving engagement with the pulley. Asis understood, when any given point lengthwise of a flexible belt comesinto contact with a pulley, it flexes to adapt itself to the curvatureof the pulley and in so doing flexes or becomes cupped transversely, thetransverse deflection increasing as the diameter of the pulleydecreases. This flexing movement tends to set up relative movementsbetween the various structural elements, but in the present belt, thistendency of the various elements to move relatively to one another, orbecome cupped, is reduced .to a minimum, or eliminated, by thetransverse reinforce means composed of the body of rubber It. At thesame time, the inner portion of the belt body, which might. be definedas that portion between the core II and the inner surface of the belt,will be free to expand laterally upon longitudinal flexing of the belt.This is due to the fact that this so-called inner portion is formedessentially of a flexible, resilient mass, free of transversereinforcements such as the hard rubber ribs in the outer portion, andthe additional fact that the inner surface of the belt is smooth andfree of any substantial indentations. This disintegration of the belt orthe separation of the several structural elements is believed to be morenoticeable where the belt is used on pulleys whose sides are adjustabletoward and from each other for the purpose of varying the speed of thebelt and the peripheral speed of the pulley so amass? that the presentinvention is especially applicable to belts designed for this usage.

existing in the usage of the belt on adjustable pulleys have givenhighly satisfactory results in that the belts so tested have stood upconsiderably longer than is the case of belts without the transversereinforce means and it is, therefore, believed that this increase oflife is largely due to the reinforce means or ribs constantlymaintaining the original cross section of the belt ss it traverses theperiphery of the pulley.

In the modified construction illustrated in Fig. 4, the transverselydisposed reinforcing members It, preferably of comparatively hard rubberare actually formed separately and embedded in the body of comparativelysoft rubber l1. As indicated in this modification, the intermediatelayer ll of fabric may be omitted. Also, as shown in this form of theinvention, the covering fabric ll may extend entirely" around the belt,this point being optional regardless of the presence or absence offabric ll.

While reference has been made to use of the present belt on groovedpulleys only, it will be understood that it is susceptible of use withother forms of drives embodying one or more grooved pulleys incombination with other types of pulleys.

What I claim is:

Actual tests 1 with belts of this construction under conditions I) l. Alongitudinally flexible belt having inner ing of the outer portion ofthe belt is prevented,

said members being spaced from one another longitudinally of the beltand a flller of resilient flexible material between said members wherebylongitudinal flexing of the belt is augmented, the belt body betweensaid core and inner surface being formed of resilient material and theinner surface of the belt being substantially free of indentationswhereby said inner portion will expand laterally when the belt is flexedlongitudina ly.

2. A longitudinally flexible belt having inner and outer surfaces with aneutral axis located between said surfaces, a series of substantiallyrigid reinforce members disposed transversely of the belt between saidneutral axis and said outer surface whereby transverse flexing of theouter portlon of the belt is prevented, said members being spaced fromone another longitudinally of the belt and a flller of resilientflexible material between said members whereby longitudinal flexing ofthe belt is augmented, the belt body between said neutral axis and theinner surface of the belt being formed essentially of resilient materialand being substantially smooth at the inner surface of the belt wherebyit will expand laterally under longitudinal flexing of the versely ofthe belt whereby transverse flexing of the belt is prevented, said bodyof hard rubber being flexible longitudinally of said belt, the innerportion of the body of said belt between the amass? said inner surfaceand the plane of said neutral axis being formed of resilient, expandiblematerial and said inner surface being free of ribs of weakness formedtherein transversely of the belt whereby the latter can flexlongitudinally, and a continuous body of resilient material between theplane of the neutral axis and the inner surface of the belt, said innersurface being smooth and substantially free of indentations whereby saidbody of resilient material will expand laterally when the belt is flexedlongitudinally.

5. A flexible-belt inner and outer surfaces with a neutral axis locatedin a plane intermediate said surfaces, longitudinally spaced,comparatively hard rubber members extending transversely of the beltbetween said outer surface and the plane of the neutral axis, saidmembers being substantially rigid transversely of the belt but flexibleas a group longitudinally of the belt, a filler of resilient, flexiblematerial between said hard rubber members imparting a smooth outersurface to the belt, and whereby longitudinal flexing of the belt isaugmented and a continuous flexible resilient inner body portion betweensaid inner-surface and the plane of the neutral axis, said inner surfacebeing substantially smooth and free of indentations whereby saidresilient inner body portion will expand laterally when said belt flexeslongitudinally.

ERNEST NASSIMBENE.

